3 ms·

> My mask protects you, your mask protects me". There is no physics behind this, masks aren't one way barriers, were never studied or sold as such, nor are they

> My mask protects you, your mask protects me". There is no physics behind this, masks aren't one way barriers, were never studied or sold as such, nor are they capable of stopping the sort of explosive air pressure caused by a cough. The proposed mechanism is that during exhalation (or more importantly speaking and coughing) there are relatively large droplets of saliva/mucus containing viral particles, and these droplets can be catched by masks (they are big and move more balistically, so masks need not be airtight). But once these droplets are in air, they dry to (much smaller) aerosol that cannot be catched by masks, you would need properly fitted FFP2/3 respirator.

native_samples 5y ago
If that were the way the virus spread, pre/asymptomatic transmission wouldn't be noticeable. There's lots of debate about whether that's really how respiratory viruses spread, but more importantly, we know it can't be that simple because we can see the effect mask mandates had on case curves (there wasn't any). So however they're theorized to work, real world data disagrees. There can be lots of reasons for this that aren't even related to mask material, e.g. most transmission occurs in homes, care homes and hospitals, all places where you'd expect most transmission to take place because people have to be confined in a small space with other sick people for long periods, and also places where you can't make people wear masks all the time.